Motion picture camera comprising an externally attached detachable cassette

ABSTRACT

A film guide is provided on the camera body. Film path means are provided on the cassette. A rigid film channel is defined outside the film gate region between the camera body and the cassette.

United States Patent 1191 Blaschek 1 1 11 j {3,833,292 1 Sept. 3, 1974 MOTION PICTURE CAMERA COMPRISING AN EXTERNALLY ATTACHED DETACHABLE CASSETTE [76] Inventor: Otto Blaschek, 81 Domach Anwanderweg 6, 8 Munich, Germany 22 Filed: Mar. 21, 1972 [21] Appl. No.: 236,610

[30] Foreign Application Priority Data Mar. 25, 1971 Germany 2114485 52 US. Cl. .(352/77 [51] Int. Cl. G031) 23/02 [58] Field of Search 352/72, 77,178 r [56] References Cited I UNITEDSTATES PATENTS 1,863,066 6/1932 Owens 35273521 2,l"32,714 10/1938 Wittelet a1. 352/77' 571; A film guide is provided on the camera body, Film path means are provided on the cassette. A rigid film channel is defined outside the film gate region be- 2,175,538 10/1939 Morsbach et 211...... 352/77 2,183,068 12/1939 Goldhammer 352/77 2,241,265 5/1941 Lechleimer 352/77 X 2,277,695 3/1942 Foster 352/77 2,339,202 1/1944 Stechbart.... 352/72 X 2,351,886 6/1944 Sperry 352/77 2,462,083 2/1949 Foster 352/77 2,505,231 4/1950 Coutant et al. 352/77 X FOREIGN PATENTS OR APPLICATIONS 641,249 8/1950 Great Britain 352/78 R Primary ExaminerSamuel S. Matthews Assistant EJ caminerA1an Mathews Attorney, Agent, or Firm-Fleit, Gipple & Jacobson ABSTRACT tween the camera body and the cassette.

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1. MOTION PICTURE CAMERA COMPRISING AN EXTERNALLY ATTACHED DETACHABLE CASSETTE "This cushioning results in high friction, the exact amount of which can be estimated only with difficulty. High friction may result in an increased wear of the film and in its tearing at the perforations. The cushioning of the cassette, or of its film path means, against the body of the motion picture camera'is particularly undesirable when the film is moved'at a high speed because the camera is'operated with a large number of frames per second. This involves'the risk that the pull-down claw moving at high speed lifts off the pressure plate as a result of the inertia forces and of the friction of the pointed ends of the pull-down claw in the'perforations of the film. In this case the film is nolonger properly guided. If the spring force is increased to prevent a lifting of the pressure plate, the risk of a tearing of the per- It is alsodesired to exchange the cassette as quickly as possible so that the camera is again ready for operation. The film path means of the cassette must be mounted in a proper orientation on the filmguide of the camera body and must be reliably'held in position when a satisfactory operation is to be ensured. Known camerasdo not sufficiently meet these requirements. Inaccuracies in the manufacture may even increase the posed according to the invention to resiliently cushion either the film path means of the cassette, whichfilm path means carry the stops, or the film guide of the camera body, which filmguide is provided with the abutment ledges. Under the pressure of the attached cassette, the film path means of the camera or the film guide of the camera body yields resiliently when the stops abut the ledges so that a proper fit and a satisfactory configuration of the rigid film channel are ensured whereas there is no need to adhere to very small toleran'ces in the manufacture of the. locking means for the cassette and of the ledges and stops which form the rigid film channel.

A spring-loaded pressure plate bearing on the moving film is suitably provided adjacent to the film gate. By this pressure plate, the film is exactly guided only adjacent to the film gate, where such exact guidance is required to ensure high-quality pictures. On the other hand, the film can move in the rigid film channel without being exposed to a substantial wear or substantial stresses by friction.

In known cameras it is often difficult to mount the at- 'tachable cassette in the proper orientation. For this reason it is a further feature of the invention that an application vof the cassette in the proper orientation is ensured in that the cassette is exactly guided only during the last portion of its movement between it is locked in undesired friction forces so that the operation is adversely affected.

Ithas been an object of the inventor so to improve a motion picture camera of the kind defined first hereinbefore that an exact and low-friction guidance of the film is ensured and the loading of the film into the cassette and the exchange-of cassettes can be quickly and reliably effected.

This objectis accomplished according to the invention that a rigid film channel is defined outside the film gate region between the camera body and the cassette when the cassette is attached to the camera body. This rigid filrn channel permits of a satisfactory, low-friction guidance of the film so that the manipulation of the camera is improved and its satisfactory operation is ensured. Even at high speeds, the film is well protected in the film channel according to'the invention and need not be guided by pressure plates biased by large spring.

mensions and enables a guidanceof the film with low friction.

Because the cassette is held by locking means when it is attached on the camera body,'it is difficult in the manufacture'of the camera to ensure an exact fitting of the stops on the film path means of the cassette on the abutment ledges of the camera body. To avoid double fits which may be due to such arrangements, it is-pro- To enable a fast exchange of cassettes, it must be possible easily to load the-film into the cassette and to remove the film from the cassette. For this reason, it is an advantageous feature of the motion picture camera that the-single-chamber cassette is diagonally divided. This is suitably accomplished'by the use of a hinged cover, which diagonally divides the cassette.

An embodiment'of the invention will now be explained more fully and by way of example on the drawing, in which:

FIG. 1 is a side elevation showing the cassette,

FIG. 2 is a front elevation showing the cassette without a cassette cover,

3 is a sectional view taken on line A-B of FIG. 2,

FIG. 4 is a top plan view showing the film path means of the cassettewithout a loop former,

' FIG. Sis a sectional view showing the film path FIG. 10 is an enlarged front elevation showing the track for the film cassette, and

FIG. 11 is a side elevation showing the camera body.

As is apparent from FIG. 1, a cassette cover 2 of a I cassette 1 can be swung about a hinge 3. As is apparent from FIGS. 1 and 3, the-cassette is diagonally divided by the cassette cover 2 along a diagonal which extends approximately from the hinges 3 disposed at the lower edge of the top of the cassette to locking means 4 provided in the lower portion of the forward face of the cassette 1.

FIG. 2 is a front elevation showing the cassette 1 with the cassette cover 2 removed. The housing provided adjacent to the film path means 5 and to a loop former 6 detachably mounted thereon is shown partly in section. The loop former is no part of the present invention. The detent projections 8 and 10 of the cassette I serve to retain the same on the motion picture camera body.

FIG. 4 is a top planview showing film path means withouta loop former. When the cassette is attached to the camera body, stops 25 bear on abutment ledges 26 of the motion picture camera body (see FIG. 9). Because the stops 25 rest on the ledges 26, the formation of a rigid film channelhaving constant dimensions is ensured. Only adjacent to film'gate 27 (FIG. 9) does a spring-loaded pressure plate 28 (FIG. 4) bear on the moving film. FIG. 8 is an enlarged sectional view showing the film path means. The stops 25 are secured to the film path means by screws 29 and consist of webs which extend transversely'to the longitudinal direction of the film. As is apparent from FIG. 4, these webs protrude laterally from the film path means. The filrnpressure plate28 is cushioned by a coil spring 30.

A film path member 36 is carried by Belleville springs path member compensates any tolerances which are inevitably involved in machining. When the cassette 1 is mounted on the motion picture camera, the stops 25 bear on the pressure ledges 26 of the camera body under the pressure of the Belleville springs 37.

A camera body 44 has a hook-in opening 45, into which the detent nose 8 of the cassette 1 is inserted when the latter is to be attached. The cassette is then swung about the hook-in opening 45 until the detent nose 10 enters the funnel-shaped entrance portion of the track 46 and snaps behind the detent hooks 47 at the end of the track (FIG. 11). The track 46 comprises a track portion 48, which positively defines the location of the cassette 1 on thecamera body. To disengage the locking member 47, a lever 49 must be pivotally moved.

In the motion picture camera which has been described hereinbefore and comprises an externally attached, detachable cassette, the film guide means comprising a film gate and a lateral film guide form part of the camera. The quick-change cassette 1 carries the second part of the film guide means, including the pressure plate 28 of the film gate. Only adjacent to the film gate 27 is the film slightly urged against the film plane. Above and below the film gate, the film moves through a rigid channel, which provides a clearance. The sliding surfaces are wellaccessible and are well protected because they are somewhat recessed. I

The loading of the camera is simplified because the cassette opens diagonally and is provided with a hinged guided in its continued movement by the engagement of the second detentnose 10, provided on the opposite side, in a recess 46, 48 provided for thispurpose on the housing, until the cassette finally engages its abutment and the locking means snap in.

What is claimed is:

1. In the combination of a motion picture camera having a film guide and a film gate region and a cassette which is externally and detachably mountable on the camera and has film path forming means, the improvement comprising stops provided on the film path forming means of the cassette, ledges provided on the camera and positioned laterally of the film guide on the camera, means for detachably mounting the cassette on the camera, said stops and ledges being independent of the mounting means and positioned so as to abut when the cassette is mounted on the camera and to form a rigid film channel above and below the film gate of the camera and between the camera body and the cassette, means for resiliently cushioning the film path forming means of the cassette, and pressure plate means mounted on the cassette for bearing on the film adjacent to the film gate of the camera.

2. The combination according to claim 1 and further comprising means for ensuring the proper orientation of the cassette relative to the camera including means for guiding the cassette as it is mounted onthe camera.

3. The combination according to claim 1 in which the cassette comprises a hinged cover approximately diagonally dividing the cassette. 

1. In the combination of a motion picture camera having a film guide and a film gate region and a cassette which is externally and detachably mountable on the camera and has film path forming means, the improvement comprising stops provided on the film path forming means of the cassette, ledges provided on the camera and positioned laterally of the film guide on the camera, means for detachably mounting the cassette on the camera, said stops and ledges being independent of the mounting means and positioned so as to abut when the cassette is mounted on the camera and to form a rigid film channel above and below thE film gate of the camera and between the camera body and the cassette, means for resiliently cushioning the film path forming means of the cassette, and pressure plate means mounted on the cassette for bearing on the film adjacent to the film gate of the camera.
 2. The combination according to claim 1 and further comprising means for ensuring the proper orientation of the cassette relative to the camera including means for guiding the cassette as it is mounted on the camera.
 3. The combination according to claim 1 in which the cassette comprises a hinged cover approximately diagonally dividing the cassette. 